In the automotive industry, it has become known to use interior trim components such as interior door panels, dashboards, and the like having a decorative covering including two different cover materials on the same trim component. Such a trim component having a two-part cover material is desired by consumers, for example to achieve a "two-tone effect" in which the two different cover materials have different colors, or a high value or "luxury effect" in which the two different cover materials are different types of materials such as a decorative cover film and a decorative cloth, or in which the different cover materials have different degrees of "soft touch" padding or the like.
In order to make such vehicle trim components having two-part cover materials, it has conventionally been the practice to splice together the two different cover materials before applying the spliced cover sheet onto the substrate of the trim component. The splicing of the two different cover materials has conventionally been carried out by thermal welding, adhesive bonding, or stitching. After the two different cover materials have been spliced together in such a manner, it is generally necessary to hide or cover the splice line in order to hide the stitching or any adhesive overspill or the like. This is conventionally achieved by applying a trim strip, such as a strip of plastic, chrome, wood or the like, over the splice line on the finished trim component. Alternatively, it has been attempted to press the splice line into a groove provided in the substrate in order to hide the splice line in this manner.
The above described conventional practices and the resulting trim component having a two-part cover material suffer many disadvantages, including the following. The preliminary process of splicing together the two different cover materials involves extra processing and handling steps, which translates into increased costs and a greater likelihood of defective parts leading to a higher reject rate. Furthermore, the application of a trim strip to hide the splice line on the finished door panel, dashboard or the like requires extra steps and extra materials, which again lead to higher costs and higher defect rates.
Most importantly, the previously known methods for making a trim component having a two-part cover material require extreme precision in forming the splice between the two different cover materials, then aligning the spliced two-part cover material onto the substrate of the trim component, and aligning the splice line with the groove provided in the substrate and/or aligning the splice trim strip with the splice line. It has been found in practice that this high degree of precision cannot be reliably attained, and as a result, the splice line is left at least partially visible in the finished trim component, i.e. the splice line protrudes out of the groove in the substrate or protrudes from under the splice trim strip. This leads to an unacceptably high reject rate of the finished trim components.
Moreover, in the operation for pressing the splice line into a groove provided in the substrate, it has been necessary to preform the groove in the substrate, which requires extra processing steps, and it has been necessary to make the groove wide enough to provide a sufficient tolerance range so that a tucking blade can press the splice line of the cover material down into the groove and then be retracted. In other words, the groove in the substrate conventionally has to be wide enough to allow for the thickness of the two layers of the cover material on both sides of the splice and for the thickness of the tucking blade that presses the cover material into the groove. After the tucking blade is retracted, however, a gap necessarily remains where the tucking blade had been pressed in. In any event, the result in the finished trim component has been unsatisfactory, because of the above mentioned defects in alignment of the splice line with the groove, but also because of the width of the conventional groove, which does not have a "closed" and "crisp" appearance.